1. Field of Invention
The present invention relates to an emergency lighting equipment and charge/discharge method. More particularly, the present invention relates to an emergency lighting equipment with automatic charge/discharge and monitoring system.
2. Description of Related Art
Emergency lighting equipment is an electrical appliance with a long history. The equipment provides some form of illumination to prevent accidents from happening when normal power is suddenly cut. Although most emergency lighting systems currently in the market have had many improvements, some problems including effective working life, damage warning and aesthetic appeal still need to be addressed.
At present, most emergency lighting systems on sale in the market have a working life of only one to two years. Moreover, system failure is often found after an actual power outage has occurred. Because the emergency lighting system is used mainly to prevent accidents, their failure is a serious concern. The short working life of the emergency lighting system is also of great concern to the environmentalists because a substantial number of the systems must be replaced each year. The failure of most automatic lighting system lies typically in an inappropriate design of the battery charging/discharging unit. In general, once an emergency lighting system is installed, nobody would take care to inspect and maintain the system periodically. Furthermore, most manufacturers are concerned about providing additional functions to the emergency lighting system and improving its outlook such as installing fluorescent lamp instead of tungsten lamp. In other words, the battery in the lighting system is in a constant float-charging stage after installation unless there is an actual power outage. Since prolonged charging is likely to shorten the working life of a battery, the emergency lighting system has a short useful life.
Due to cost consideration, most emergency lighting systems have no low voltage inspection circuits. In other words, the internal electronic circuits are still in the discharging state long after the battery is completely discharged. When the power outage period is long, the emergency lighting system is still in the discharging state even after all energy is drained from the battery. Ultimately, the battery is permanently damaged.
In brief, conventional emergency lighting systems have the following drawbacks: 1. The battery inside an emergency lighting system is in a float-charging state so that the system can have a maximum working life of between one to two years. Furthermore, failure is only found after an actual power outage has occurred. 2. Since there is no low voltage inspection circuit inside the system, the battery may be permanently damaged by over-discharge. 3. There is little control over the discharge current in an emergency lighting system. Thus, the system will stop providing any illumination after a while if the power outage is long.